The thermal transition behaviour, optical and structural properties of spin-coated P3HT:C60 blended films with different C60 ratios were investigated using differential scanning calorimetry (DSC), thermo-gravimetric analysis (TGA), ultraviolet–visible (UV–vis) spectroscopy, photoluminescence (PL), fourier transform infrared absorption (FT-IR) spectroscopy and raman spectroscopy. DSC analysis showed that
the P3HT:C60 blends have quite different thermal characteristics. The absorption spectra of the annealed P3HT:C60 (1:1wt%) films becomes enhanced and red shifted. This feature is evident in the photoluminescence measurements where the formation of polymer crystallites upon annealing is observed. Raman spectroscopy showed a substantial ordering in the polymer film during annealing. It was found that the performance of a P3HT:C60 (1:1wt%) device was dramatically improved by annealing.

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Copyright: 2009 Elsevier. This is the author's version of the work. It is posted here by permission of Elsevier for your personal use. Not for redistribution. The definitive version was published in the journal, Solar Energy Materials and Solar Cells, Vol. 93(9), pp 1674-1680